1 /* 2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #include "zstd_compress_internal.h" 12 #include "zstd_double_fast.h" 13 14 15 void ZSTD_fillDoubleHashTable(ZSTD_matchState_t* ms, 16 void const* end, ZSTD_dictTableLoadMethod_e dtlm) 17 { 18 const ZSTD_compressionParameters* const cParams = &ms->cParams; 19 U32* const hashLarge = ms->hashTable; 20 U32 const hBitsL = cParams->hashLog; 21 U32 const mls = cParams->minMatch; 22 U32* const hashSmall = ms->chainTable; 23 U32 const hBitsS = cParams->chainLog; 24 const BYTE* const base = ms->window.base; 25 const BYTE* ip = base + ms->nextToUpdate; 26 const BYTE* const iend = ((const BYTE*)end) - HASH_READ_SIZE; 27 const U32 fastHashFillStep = 3; 28 29 /* Always insert every fastHashFillStep position into the hash tables. 30 * Insert the other positions into the large hash table if their entry 31 * is empty. 32 */ 33 for (; ip + fastHashFillStep - 1 <= iend; ip += fastHashFillStep) { 34 U32 const current = (U32)(ip - base); 35 U32 i; 36 for (i = 0; i < fastHashFillStep; ++i) { 37 size_t const smHash = ZSTD_hashPtr(ip + i, hBitsS, mls); 38 size_t const lgHash = ZSTD_hashPtr(ip + i, hBitsL, 8); 39 if (i == 0) 40 hashSmall[smHash] = current + i; 41 if (i == 0 || hashLarge[lgHash] == 0) 42 hashLarge[lgHash] = current + i; 43 /* Only load extra positions for ZSTD_dtlm_full */ 44 if (dtlm == ZSTD_dtlm_fast) 45 break; 46 } 47 } 48 } 49 50 51 FORCE_INLINE_TEMPLATE 52 size_t ZSTD_compressBlock_doubleFast_generic( 53 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 54 void const* src, size_t srcSize, 55 U32 const mls /* template */, ZSTD_dictMode_e const dictMode) 56 { 57 ZSTD_compressionParameters const* cParams = &ms->cParams; 58 U32* const hashLong = ms->hashTable; 59 const U32 hBitsL = cParams->hashLog; 60 U32* const hashSmall = ms->chainTable; 61 const U32 hBitsS = cParams->chainLog; 62 const BYTE* const base = ms->window.base; 63 const BYTE* const istart = (const BYTE*)src; 64 const BYTE* ip = istart; 65 const BYTE* anchor = istart; 66 const U32 prefixLowestIndex = ms->window.dictLimit; 67 const BYTE* const prefixLowest = base + prefixLowestIndex; 68 const BYTE* const iend = istart + srcSize; 69 const BYTE* const ilimit = iend - HASH_READ_SIZE; 70 U32 offset_1=rep[0], offset_2=rep[1]; 71 U32 offsetSaved = 0; 72 73 const ZSTD_matchState_t* const dms = ms->dictMatchState; 74 const ZSTD_compressionParameters* const dictCParams = 75 dictMode == ZSTD_dictMatchState ? 76 &dms->cParams : NULL; 77 const U32* const dictHashLong = dictMode == ZSTD_dictMatchState ? 78 dms->hashTable : NULL; 79 const U32* const dictHashSmall = dictMode == ZSTD_dictMatchState ? 80 dms->chainTable : NULL; 81 const U32 dictStartIndex = dictMode == ZSTD_dictMatchState ? 82 dms->window.dictLimit : 0; 83 const BYTE* const dictBase = dictMode == ZSTD_dictMatchState ? 84 dms->window.base : NULL; 85 const BYTE* const dictStart = dictMode == ZSTD_dictMatchState ? 86 dictBase + dictStartIndex : NULL; 87 const BYTE* const dictEnd = dictMode == ZSTD_dictMatchState ? 88 dms->window.nextSrc : NULL; 89 const U32 dictIndexDelta = dictMode == ZSTD_dictMatchState ? 90 prefixLowestIndex - (U32)(dictEnd - dictBase) : 91 0; 92 const U32 dictHBitsL = dictMode == ZSTD_dictMatchState ? 93 dictCParams->hashLog : hBitsL; 94 const U32 dictHBitsS = dictMode == ZSTD_dictMatchState ? 95 dictCParams->chainLog : hBitsS; 96 const U32 dictAndPrefixLength = (U32)(ip - prefixLowest + dictEnd - dictStart); 97 98 assert(dictMode == ZSTD_noDict || dictMode == ZSTD_dictMatchState); 99 100 /* init */ 101 ip += (dictAndPrefixLength == 0); 102 if (dictMode == ZSTD_noDict) { 103 U32 const maxRep = (U32)(ip - prefixLowest); 104 if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0; 105 if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0; 106 } 107 if (dictMode == ZSTD_dictMatchState) { 108 /* dictMatchState repCode checks don't currently handle repCode == 0 109 * disabling. */ 110 assert(offset_1 <= dictAndPrefixLength); 111 assert(offset_2 <= dictAndPrefixLength); 112 } 113 114 /* Main Search Loop */ 115 while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */ 116 size_t mLength; 117 U32 offset; 118 size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8); 119 size_t const h = ZSTD_hashPtr(ip, hBitsS, mls); 120 size_t const dictHL = ZSTD_hashPtr(ip, dictHBitsL, 8); 121 size_t const dictHS = ZSTD_hashPtr(ip, dictHBitsS, mls); 122 U32 const current = (U32)(ip-base); 123 U32 const matchIndexL = hashLong[h2]; 124 U32 matchIndexS = hashSmall[h]; 125 const BYTE* matchLong = base + matchIndexL; 126 const BYTE* match = base + matchIndexS; 127 const U32 repIndex = current + 1 - offset_1; 128 const BYTE* repMatch = (dictMode == ZSTD_dictMatchState 129 && repIndex < prefixLowestIndex) ? 130 dictBase + (repIndex - dictIndexDelta) : 131 base + repIndex; 132 hashLong[h2] = hashSmall[h] = current; /* update hash tables */ 133 134 /* check dictMatchState repcode */ 135 if (dictMode == ZSTD_dictMatchState 136 && ((U32)((prefixLowestIndex-1) - repIndex) >= 3 /* intentional underflow */) 137 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { 138 const BYTE* repMatchEnd = repIndex < prefixLowestIndex ? dictEnd : iend; 139 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixLowest) + 4; 140 ip++; 141 ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); 142 goto _match_stored; 143 } 144 145 /* check noDict repcode */ 146 if ( dictMode == ZSTD_noDict 147 && ((offset_1 > 0) & (MEM_read32(ip+1-offset_1) == MEM_read32(ip+1)))) { 148 mLength = ZSTD_count(ip+1+4, ip+1+4-offset_1, iend) + 4; 149 ip++; 150 ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); 151 goto _match_stored; 152 } 153 154 if (matchIndexL > prefixLowestIndex) { 155 /* check prefix long match */ 156 if (MEM_read64(matchLong) == MEM_read64(ip)) { 157 mLength = ZSTD_count(ip+8, matchLong+8, iend) + 8; 158 offset = (U32)(ip-matchLong); 159 while (((ip>anchor) & (matchLong>prefixLowest)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ 160 goto _match_found; 161 } 162 } else if (dictMode == ZSTD_dictMatchState) { 163 /* check dictMatchState long match */ 164 U32 const dictMatchIndexL = dictHashLong[dictHL]; 165 const BYTE* dictMatchL = dictBase + dictMatchIndexL; 166 assert(dictMatchL < dictEnd); 167 168 if (dictMatchL > dictStart && MEM_read64(dictMatchL) == MEM_read64(ip)) { 169 mLength = ZSTD_count_2segments(ip+8, dictMatchL+8, iend, dictEnd, prefixLowest) + 8; 170 offset = (U32)(current - dictMatchIndexL - dictIndexDelta); 171 while (((ip>anchor) & (dictMatchL>dictStart)) && (ip[-1] == dictMatchL[-1])) { ip--; dictMatchL--; mLength++; } /* catch up */ 172 goto _match_found; 173 } 174 } 175 176 if (matchIndexS > prefixLowestIndex) { 177 /* check prefix short match */ 178 if (MEM_read32(match) == MEM_read32(ip)) { 179 goto _search_next_long; 180 } 181 } else if (dictMode == ZSTD_dictMatchState) { 182 /* check dictMatchState short match */ 183 U32 const dictMatchIndexS = dictHashSmall[dictHS]; 184 match = dictBase + dictMatchIndexS; 185 matchIndexS = dictMatchIndexS + dictIndexDelta; 186 187 if (match > dictStart && MEM_read32(match) == MEM_read32(ip)) { 188 goto _search_next_long; 189 } 190 } 191 192 ip += ((ip-anchor) >> kSearchStrength) + 1; 193 continue; 194 195 _search_next_long: 196 197 { 198 size_t const hl3 = ZSTD_hashPtr(ip+1, hBitsL, 8); 199 size_t const dictHLNext = ZSTD_hashPtr(ip+1, dictHBitsL, 8); 200 U32 const matchIndexL3 = hashLong[hl3]; 201 const BYTE* matchL3 = base + matchIndexL3; 202 hashLong[hl3] = current + 1; 203 204 /* check prefix long +1 match */ 205 if (matchIndexL3 > prefixLowestIndex) { 206 if (MEM_read64(matchL3) == MEM_read64(ip+1)) { 207 mLength = ZSTD_count(ip+9, matchL3+8, iend) + 8; 208 ip++; 209 offset = (U32)(ip-matchL3); 210 while (((ip>anchor) & (matchL3>prefixLowest)) && (ip[-1] == matchL3[-1])) { ip--; matchL3--; mLength++; } /* catch up */ 211 goto _match_found; 212 } 213 } else if (dictMode == ZSTD_dictMatchState) { 214 /* check dict long +1 match */ 215 U32 const dictMatchIndexL3 = dictHashLong[dictHLNext]; 216 const BYTE* dictMatchL3 = dictBase + dictMatchIndexL3; 217 assert(dictMatchL3 < dictEnd); 218 if (dictMatchL3 > dictStart && MEM_read64(dictMatchL3) == MEM_read64(ip+1)) { 219 mLength = ZSTD_count_2segments(ip+1+8, dictMatchL3+8, iend, dictEnd, prefixLowest) + 8; 220 ip++; 221 offset = (U32)(current + 1 - dictMatchIndexL3 - dictIndexDelta); 222 while (((ip>anchor) & (dictMatchL3>dictStart)) && (ip[-1] == dictMatchL3[-1])) { ip--; dictMatchL3--; mLength++; } /* catch up */ 223 goto _match_found; 224 } 225 } 226 } 227 228 /* if no long +1 match, explore the short match we found */ 229 if (dictMode == ZSTD_dictMatchState && matchIndexS < prefixLowestIndex) { 230 mLength = ZSTD_count_2segments(ip+4, match+4, iend, dictEnd, prefixLowest) + 4; 231 offset = (U32)(current - matchIndexS); 232 while (((ip>anchor) & (match>dictStart)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ 233 } else { 234 mLength = ZSTD_count(ip+4, match+4, iend) + 4; 235 offset = (U32)(ip - match); 236 while (((ip>anchor) & (match>prefixLowest)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ 237 } 238 239 /* fall-through */ 240 241 _match_found: 242 offset_2 = offset_1; 243 offset_1 = offset; 244 245 ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); 246 247 _match_stored: 248 /* match found */ 249 ip += mLength; 250 anchor = ip; 251 252 if (ip <= ilimit) { 253 /* Fill Table */ 254 hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = 255 hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; /* here because current+2 could be > iend-8 */ 256 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = 257 hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base); 258 259 /* check immediate repcode */ 260 if (dictMode == ZSTD_dictMatchState) { 261 while (ip <= ilimit) { 262 U32 const current2 = (U32)(ip-base); 263 U32 const repIndex2 = current2 - offset_2; 264 const BYTE* repMatch2 = dictMode == ZSTD_dictMatchState 265 && repIndex2 < prefixLowestIndex ? 266 dictBase - dictIndexDelta + repIndex2 : 267 base + repIndex2; 268 if ( ((U32)((prefixLowestIndex-1) - (U32)repIndex2) >= 3 /* intentional overflow */) 269 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) { 270 const BYTE* const repEnd2 = repIndex2 < prefixLowestIndex ? dictEnd : iend; 271 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixLowest) + 4; 272 U32 tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ 273 ZSTD_storeSeq(seqStore, 0, anchor, 0, repLength2-MINMATCH); 274 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2; 275 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2; 276 ip += repLength2; 277 anchor = ip; 278 continue; 279 } 280 break; 281 } 282 } 283 284 if (dictMode == ZSTD_noDict) { 285 while ( (ip <= ilimit) 286 && ( (offset_2>0) 287 & (MEM_read32(ip) == MEM_read32(ip - offset_2)) )) { 288 /* store sequence */ 289 size_t const rLength = ZSTD_count(ip+4, ip+4-offset_2, iend) + 4; 290 U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; /* swap offset_2 <=> offset_1 */ 291 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip-base); 292 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip-base); 293 ZSTD_storeSeq(seqStore, 0, anchor, 0, rLength-MINMATCH); 294 ip += rLength; 295 anchor = ip; 296 continue; /* faster when present ... (?) */ 297 } } } } 298 299 /* save reps for next block */ 300 rep[0] = offset_1 ? offset_1 : offsetSaved; 301 rep[1] = offset_2 ? offset_2 : offsetSaved; 302 303 /* Return the last literals size */ 304 return iend - anchor; 305 } 306 307 308 size_t ZSTD_compressBlock_doubleFast( 309 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 310 void const* src, size_t srcSize) 311 { 312 const U32 mls = ms->cParams.minMatch; 313 switch(mls) 314 { 315 default: /* includes case 3 */ 316 case 4 : 317 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_noDict); 318 case 5 : 319 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_noDict); 320 case 6 : 321 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_noDict); 322 case 7 : 323 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_noDict); 324 } 325 } 326 327 328 size_t ZSTD_compressBlock_doubleFast_dictMatchState( 329 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 330 void const* src, size_t srcSize) 331 { 332 const U32 mls = ms->cParams.minMatch; 333 switch(mls) 334 { 335 default: /* includes case 3 */ 336 case 4 : 337 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 4, ZSTD_dictMatchState); 338 case 5 : 339 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 5, ZSTD_dictMatchState); 340 case 6 : 341 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 6, ZSTD_dictMatchState); 342 case 7 : 343 return ZSTD_compressBlock_doubleFast_generic(ms, seqStore, rep, src, srcSize, 7, ZSTD_dictMatchState); 344 } 345 } 346 347 348 static size_t ZSTD_compressBlock_doubleFast_extDict_generic( 349 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 350 void const* src, size_t srcSize, 351 U32 const mls /* template */) 352 { 353 ZSTD_compressionParameters const* cParams = &ms->cParams; 354 U32* const hashLong = ms->hashTable; 355 U32 const hBitsL = cParams->hashLog; 356 U32* const hashSmall = ms->chainTable; 357 U32 const hBitsS = cParams->chainLog; 358 const BYTE* const istart = (const BYTE*)src; 359 const BYTE* ip = istart; 360 const BYTE* anchor = istart; 361 const BYTE* const iend = istart + srcSize; 362 const BYTE* const ilimit = iend - 8; 363 const U32 prefixStartIndex = ms->window.dictLimit; 364 const BYTE* const base = ms->window.base; 365 const BYTE* const prefixStart = base + prefixStartIndex; 366 const U32 dictStartIndex = ms->window.lowLimit; 367 const BYTE* const dictBase = ms->window.dictBase; 368 const BYTE* const dictStart = dictBase + dictStartIndex; 369 const BYTE* const dictEnd = dictBase + prefixStartIndex; 370 U32 offset_1=rep[0], offset_2=rep[1]; 371 372 DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_extDict_generic (srcSize=%zu)", srcSize); 373 374 /* Search Loop */ 375 while (ip < ilimit) { /* < instead of <=, because (ip+1) */ 376 const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls); 377 const U32 matchIndex = hashSmall[hSmall]; 378 const BYTE* const matchBase = matchIndex < prefixStartIndex ? dictBase : base; 379 const BYTE* match = matchBase + matchIndex; 380 381 const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8); 382 const U32 matchLongIndex = hashLong[hLong]; 383 const BYTE* const matchLongBase = matchLongIndex < prefixStartIndex ? dictBase : base; 384 const BYTE* matchLong = matchLongBase + matchLongIndex; 385 386 const U32 current = (U32)(ip-base); 387 const U32 repIndex = current + 1 - offset_1; /* offset_1 expected <= current +1 */ 388 const BYTE* const repBase = repIndex < prefixStartIndex ? dictBase : base; 389 const BYTE* const repMatch = repBase + repIndex; 390 size_t mLength; 391 hashSmall[hSmall] = hashLong[hLong] = current; /* update hash table */ 392 393 if ((((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex doesn't overlap dict + prefix */ 394 & (repIndex > dictStartIndex)) 395 && (MEM_read32(repMatch) == MEM_read32(ip+1)) ) { 396 const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend; 397 mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4; 398 ip++; 399 ZSTD_storeSeq(seqStore, ip-anchor, anchor, 0, mLength-MINMATCH); 400 } else { 401 if ((matchLongIndex > dictStartIndex) && (MEM_read64(matchLong) == MEM_read64(ip))) { 402 const BYTE* const matchEnd = matchLongIndex < prefixStartIndex ? dictEnd : iend; 403 const BYTE* const lowMatchPtr = matchLongIndex < prefixStartIndex ? dictStart : prefixStart; 404 U32 offset; 405 mLength = ZSTD_count_2segments(ip+8, matchLong+8, iend, matchEnd, prefixStart) + 8; 406 offset = current - matchLongIndex; 407 while (((ip>anchor) & (matchLong>lowMatchPtr)) && (ip[-1] == matchLong[-1])) { ip--; matchLong--; mLength++; } /* catch up */ 408 offset_2 = offset_1; 409 offset_1 = offset; 410 ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); 411 412 } else if ((matchIndex > dictStartIndex) && (MEM_read32(match) == MEM_read32(ip))) { 413 size_t const h3 = ZSTD_hashPtr(ip+1, hBitsL, 8); 414 U32 const matchIndex3 = hashLong[h3]; 415 const BYTE* const match3Base = matchIndex3 < prefixStartIndex ? dictBase : base; 416 const BYTE* match3 = match3Base + matchIndex3; 417 U32 offset; 418 hashLong[h3] = current + 1; 419 if ( (matchIndex3 > dictStartIndex) && (MEM_read64(match3) == MEM_read64(ip+1)) ) { 420 const BYTE* const matchEnd = matchIndex3 < prefixStartIndex ? dictEnd : iend; 421 const BYTE* const lowMatchPtr = matchIndex3 < prefixStartIndex ? dictStart : prefixStart; 422 mLength = ZSTD_count_2segments(ip+9, match3+8, iend, matchEnd, prefixStart) + 8; 423 ip++; 424 offset = current+1 - matchIndex3; 425 while (((ip>anchor) & (match3>lowMatchPtr)) && (ip[-1] == match3[-1])) { ip--; match3--; mLength++; } /* catch up */ 426 } else { 427 const BYTE* const matchEnd = matchIndex < prefixStartIndex ? dictEnd : iend; 428 const BYTE* const lowMatchPtr = matchIndex < prefixStartIndex ? dictStart : prefixStart; 429 mLength = ZSTD_count_2segments(ip+4, match+4, iend, matchEnd, prefixStart) + 4; 430 offset = current - matchIndex; 431 while (((ip>anchor) & (match>lowMatchPtr)) && (ip[-1] == match[-1])) { ip--; match--; mLength++; } /* catch up */ 432 } 433 offset_2 = offset_1; 434 offset_1 = offset; 435 ZSTD_storeSeq(seqStore, ip-anchor, anchor, offset + ZSTD_REP_MOVE, mLength-MINMATCH); 436 437 } else { 438 ip += ((ip-anchor) >> kSearchStrength) + 1; 439 continue; 440 } } 441 442 /* found a match : store it */ 443 ip += mLength; 444 anchor = ip; 445 446 if (ip <= ilimit) { 447 /* Fill Table */ 448 hashSmall[ZSTD_hashPtr(base+current+2, hBitsS, mls)] = current+2; 449 hashLong[ZSTD_hashPtr(base+current+2, hBitsL, 8)] = current+2; 450 hashSmall[ZSTD_hashPtr(ip-2, hBitsS, mls)] = (U32)(ip-2-base); 451 hashLong[ZSTD_hashPtr(ip-2, hBitsL, 8)] = (U32)(ip-2-base); 452 /* check immediate repcode */ 453 while (ip <= ilimit) { 454 U32 const current2 = (U32)(ip-base); 455 U32 const repIndex2 = current2 - offset_2; 456 const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2; 457 if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) /* intentional overflow : ensure repIndex2 doesn't overlap dict + prefix */ 458 & (repIndex2 > dictStartIndex)) 459 && (MEM_read32(repMatch2) == MEM_read32(ip)) ) { 460 const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend; 461 size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4; 462 U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */ 463 ZSTD_storeSeq(seqStore, 0, anchor, 0, repLength2-MINMATCH); 464 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = current2; 465 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = current2; 466 ip += repLength2; 467 anchor = ip; 468 continue; 469 } 470 break; 471 } } } 472 473 /* save reps for next block */ 474 rep[0] = offset_1; 475 rep[1] = offset_2; 476 477 /* Return the last literals size */ 478 return iend - anchor; 479 } 480 481 482 size_t ZSTD_compressBlock_doubleFast_extDict( 483 ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], 484 void const* src, size_t srcSize) 485 { 486 U32 const mls = ms->cParams.minMatch; 487 switch(mls) 488 { 489 default: /* includes case 3 */ 490 case 4 : 491 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 4); 492 case 5 : 493 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 5); 494 case 6 : 495 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 6); 496 case 7 : 497 return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 7); 498 } 499 } 500